You can easily modify the robot by adding two more motors and two more wheels. Then, your mobile robot will be four motor driven. Obviously, you need to modify the code and add what is necessary, but this should not be a problem since the core is already coded. When changing the way that a mobile robot moves, we need to think what things this change affects. This means that the center of mass may be changed and the orbit of a movement may be different. For example, the following is a four-wheeled mobile robot:
As far as the wheels and motors are concerned, you can perform another simple change. Add crawlers to your ...